The invention relates to a recirculating-type liquid flow paint system, and more particularly to an adjustable flow rate controller for regulating the quantity of paint supply to a spray gun while allowing the excess paint to be circulated through the paint recirculating system.
Recirculating-type liquid coating, or more particularly, recirculating-type paint systems are in widespread commercial use. The paint recirculating system includes a mixing tank equipped with suitable agitation means maintaining the paint uniformly mixed and a pump transferring the liquid paint under pressure to a plurality of automatic or manual spray guns. Suitable return lines are provided to return the excess paint back to the mixing tank for recyling.
At the juncture of the pressurized paint supply line and spray gun, a suitable flow control device is inserted for regulating the quantity and pressure of the paint to be supplied directly to the spray gun.
Various flow control devices or paint restrictor device have been used or proposed for use, including diaphragm-type regulators, and needle-valve regulators. Some of the prior art constructions have been handicapped by their tendency to become progressively plugged over periods of use, necessitating excessive down time for cleaning or replacement of the regulators. Additionally, some of the prior art devices are difficult to adjust the flow rate in, often requiring removal and tools to adjust.
U.S. Pat. No. 4,106,699 issued to Holt on Aug. 15, 1978 discloses a needle-valve type flow regulator which, although, embodying some needed self-cleaning features, requires stoppage of the paint flow, partial disassembly, and use of a tool to adjust flow rate.